Superconducting device having a reduced thickness of oxide superconducting layer and method for manufacturing the same

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EP 0 475 838 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	08.07.1992 Bulletin 1992/28

(43)	Date of publication A2:
	18.03.1992 Bulletin 1992/12

(21)	Application number: 91402409.6

(22)	Date of filing: 10.09.1991

(51)	International Patent Classification (IPC)⁵: H01L 39/22, H01L 39/24

(84)	Designated Contracting States:
	DE FR GB

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Priority:

10.09.1990 JP 239423/90
27.09.1990 JP 257853/90

(71)	Applicant: Sumitomo Electric Industries, Ltd.
	Osaka 541 (JP)

(72)	Inventors:
	Nakamura, Takao F-75116 Paris (FR) Inada, Hiroshi F-75116 Paris (FR) Iiyama, Michitomo F-75116 Paris (FR)

(74)	Representative: Ballot, Paul Denis Jacques et al
	Cabinet Ballot-Schmit, 7, rue Le Sueur 75116 Paris 75116 Paris (FR)

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References cited: :

(54)	Superconducting device having a reduced thickness of oxide superconducting layer and method for manufacturing the same

(57) A superconducting device comprises first and second oxide superconducing regions of a relatively thick thickness formed directly on a principal surface of a substrate separately from each other, and a third oxide superconducting region of an extremely thin thickness formed directly on the principal surface of the substrate so as to bridge the first and second oxide superconducting regions. A barrier layer and a diffusion source layer is formed on the third oxide superconducting region, and an isolation region is formed to cover an upper portion or both side surfaces of the diffusion source layer. The first, second and third oxide superconducting regions and the isolation region are formed of the same oxide superconductor material, and the isolation region is diffused with a material of the diffusion source layer, so that the isolation region does not show superconductivity. Therefore, a superconducting current can flow between the first and second oxide superconducting regions through only the third oxide superconducting region.
For formation of the superconducting device, a first oxide superconductor thin film having a very thin thickness is formed on the principal surface of the substrate, and a barrier layer and a diffusion source layer are formed on a portion of the first oxide superconductor thin film. A second oxide superconductor thin film is grown on an exposed surface of the first oxide superconductor thin film until the two layers are embedded in the second oxide superconductor thin film, so that a material of the diffusion source layer is diffused into the second oxide superconductor thin film on an upper portion or both side surfaces of the diffusion source layer.

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